h1 {
    color: green;
}

.draggable {
    border: 1px solid black;
    width: 100px;
    height: 100px;
    padding: 0.5em;
    float: left;
    margin: 10px 10px 10px 0;
}
.droppable {
    border: 1px solid black;
    width: 150px;
    height: 150px;
    padding: 0.5em;
    float: left;
    margin:  10px;
}

.drophover {
    background-color: green;
}

.invisible {
    visibility: hidden;
}
